| Objective:1.To construct the circualting tumor cells(CTCs)detection system for the subcutaneous xenograft(SX)and orthotopic xenograft(OX)mouse models of PDAC;2.To compare the characteristics of tumor growth,CTCs change and distant metastasis in two different models;3.To discuss the effect of high-intensity focused ultrasound(HIFU)treatment on CTCs change and tumor growth in pancreatic cancer model;Methods:1.Human pancreatic cancer m Cherry-Bx PC-3 cells stably expressing red fluorescence were obtained by lentiviral transfection.Afterwards,cells with high-fluorescence intensity(the brightest 1%)were sorted by fluorescence-activated cell sorting(FACS)to continue culture;2.MCherry-Bx PC-3 cells were used to build the SX model,which was used to provide tumor source.After that,we individually constructed the SX and OX models of PDAC using the tumor originated from the same tumor-bearing mouse;3.The tumor growth was evaluated by ultrasound imaging.Meanwhile,the in vivo flow cytometry(IVFC)was used to quantitative analysis the CTCs count of PDAC.Furthermore,the histopathological characteristics of the SX and OX models were compared by observing the H&E sections.Finally,all the data were collected to explore the differences between the two models.4.Before and after HIFU ablation,the CTCs number and tumor volume were real-time dynamic monitored by IVFC and ultrasound imaging in the OX model,in order to evaluate the impact of HIFU treatment on CTCs change and tumor growth.Results:1.We constructed the human-derived pancreatic cancer m Cherry-Bx PC-3 cells with stable transfection of red fluorescence.After sorting by FACS,the high-fluorescence intensity cell line was acquired.The SX and OX models of PDAC in nude mice were constructed with a 100%success rate(n=10);2.The OX model grew faster comparing to the SX model,it was statistically significant from day 10 after tumor transplantation.Furthermore,the survival time of the OX model was(19.55±2.84)days,which was significantly shorter than the SX model(55.00±8.39)days.The number of CTCs in the OX model showed an increasing trend,however,the SX model was always at a low level.Moreover,liver metastasis occurred in the 21-day after transplantation of the OX model,not in the SX model.3.The CTC count of the HIFU ablation group was(4.50±1.29)/hour,which was significantly lower than that of the untreated group(22.75±2.22)/hour.The tumor volume in the HIFU-treated group(476.20±185.12)mm~3 was significantly smaller than the tumor volume in the untreated group(682.50±150.30)mm~3,HIFU treatment effectively slowed down tumor growth.Conclusion:1.The OX model was better mimic of metastasis than the SX model,hence it was more suitable for the study of metastatic PDAC than the SX model;2.HIFU exposure would not enhance the CTC counts of PDAC in the OX tumor mice.In addition,HIFU ablation effectively suppressed local tumor growth. |
